อ้างอิง ของ ยุคหินเก่า

  1. ↑ Christian, David (2014). Big History: Between Nothing and Everything. New York: McGraw Hill Education. p. 93.
  2. ↑ Toth, Nicholas; Schick, Kathy (2007). "Handbook of Paleoanthropology". Handbook of Paleoanthropology: 1943–1963. doi:10.1007/978-3-540-33761-4_64. In Henke, H.C. Winfried; Hardt, Thorolf; Tatersall, Ian. Handbook of Paleoanthropology. Volume 3. Berlin; Heidelberg; New York: Springer-Verlag. p. 1944. (PRINT: ISBN 978-3-540-32474-4 ONLINE: ISBN 978-3-540-33761-4)